The role of TFAM-associated proteins in mitochondrial RNA metabolism

Background: Mammalian mitochondrial DNA (mtDNA) takes on a higher structure called the nucleoid or mitochromosome, which corresponds to that of nuclear DNA. Mitochondrial transcription factor A (TFAM), which was cloned as a transcription factor for mitochondrial DNA, is critical for forming this higher structure and for maintenance of mtDNA. Scope of review: To investigate the functional aspects of the nucleoid, we have identified many RNA-binding proteins to be candidate TFAM interactors, including ERAL1 and p32. Major conclusions: In this review, we would like to describe that ERAL1 binds to the mitochondrial rRNA component of the ribosomal small subunit and is an important constituent of this subunit. p32, which is involved in mitochondrial translation, may be a novel marker of clinical progression in prostate cancer. Here we describe these proteins, all of which are involved in translation within the mitochondrial matrix. General significance: This review highlights the results from the mitochondrial nucleoid research in organic biochemistry. This article is part of a Special Issue entitled Biochemistry of Mitochondria.